The vessel had a recent history of bottom contact which involved the grounding in the American Narrows and sitting on the bottom in Toledo prior to the subject bottom contact in the canal. However, reference to reports of these events and the damage involved confirmed that the underwater port bow damage was incurred when the vessel contacted the bottom in the Welland Canal on 28 April 1996. The Toledo loading berth does not have any outcrops of rock to create the type of damage sustained, and the diver reports indicated that the kind of damage found on the port bow had to have occurred while the vessel was moving ahead and was not static damage. The diver reports on the American Narrows grounding did not reveal any damage on the port side forward. At Mile No. 11, a vessel in the centre of the canal, as the STEELFLOWER was reported to be, is somewhat off the centre line of the channel, toward the east bank. Being overdraught contributed to the possibility that the stern of the STEELFLOWER experienced suction from the east bank to an extent sufficient to prevent the vessel from responding to the helm. For the vessel to contact the bottom at the side of the channel, it was not necessary for her to be at an angle of 25 to 30 degrees to the course line as described by the witness. In fact, a vessel the size of the STEELFLOWER would be aground forward and aft when less than 15 degrees to the line of the channel. It can be calculated that, proceeding at 4.5 knots, a vessel the size of the STEELFLOWER would run out of the channel within approximately 3 minutes if the five-degree alteration of course was not effected. The vessel speed was estimated at between 4.5 and 5 knots, and this did not allow the bow thruster to initially assist in turning the vessel. In the event, the bow thruster did not prevent the vessel contacting the bottom when the speed diminished, and it could not be determined with certainty whether the accident could have been averted if more than a single fin had been fitted on the kort nozzle. Although the pilot found it difficult to hold the vessel's head steady on course and indicated that he was dissatisfied with the helmsmen, it is unlikely that the vessel contacted the bottom as a result of either the design of the steering gear or of the level of competence of the helmsmen.Analysis The vessel had a recent history of bottom contact which involved the grounding in the American Narrows and sitting on the bottom in Toledo prior to the subject bottom contact in the canal. However, reference to reports of these events and the damage involved confirmed that the underwater port bow damage was incurred when the vessel contacted the bottom in the Welland Canal on 28 April 1996. The Toledo loading berth does not have any outcrops of rock to create the type of damage sustained, and the diver reports indicated that the kind of damage found on the port bow had to have occurred while the vessel was moving ahead and was not static damage. The diver reports on the American Narrows grounding did not reveal any damage on the port side forward. At Mile No. 11, a vessel in the centre of the canal, as the STEELFLOWER was reported to be, is somewhat off the centre line of the channel, toward the east bank. Being overdraught contributed to the possibility that the stern of the STEELFLOWER experienced suction from the east bank to an extent sufficient to prevent the vessel from responding to the helm. For the vessel to contact the bottom at the side of the channel, it was not necessary for her to be at an angle of 25 to 30 degrees to the course line as described by the witness. In fact, a vessel the size of the STEELFLOWER would be aground forward and aft when less than 15 degrees to the line of the channel. It can be calculated that, proceeding at 4.5 knots, a vessel the size of the STEELFLOWER would run out of the channel within approximately 3 minutes if the five-degree alteration of course was not effected. The vessel speed was estimated at between 4.5 and 5 knots, and this did not allow the bow thruster to initially assist in turning the vessel. In the event, the bow thruster did not prevent the vessel contacting the bottom when the speed diminished, and it could not be determined with certainty whether the accident could have been averted if more than a single fin had been fitted on the kort nozzle. Although the pilot found it difficult to hold the vessel's head steady on course and indicated that he was dissatisfied with the helmsmen, it is unlikely that the vessel contacted the bottom as a result of either the design of the steering gear or of the level of competence of the helmsmen. When the STEELFLOWER arrived at Port Colborne to undertake a downbound passage of the Welland Canal, she was drawing in excess of the maximum permissible Seaway draught. At the request of the SLSA, the vessel reduced her forward trim but was unable to reduce her draught to the Seaway maximum. At the request of the vessel, the SLSA were able to give the STEELFLOWER specific permission to continue her passage. The STEELFLOWER did not respond to the helm for a heading adjustment on passing Mile No. 11 and contacted the bottom at the side of the ship channel. With the vessel deeply laden and toward the east side of the ship channel, the failure to respond to the helm was likely due to bottom/bank suction. The pilot did not notify the SLSA because contacting the bottom reportedly did not involve an impact which would have suggested damage. The SLSA subsequently diverted the STEELFLOWER to Prescott to investigate the pronounced list the vessel developed as she continued through the Seaway. The damage discovered by divers on the port side of the vessel on 03 May occurred when she contacted the bottom at Mile No. 11.Findings When the STEELFLOWER arrived at Port Colborne to undertake a downbound passage of the Welland Canal, she was drawing in excess of the maximum permissible Seaway draught. At the request of the SLSA, the vessel reduced her forward trim but was unable to reduce her draught to the Seaway maximum. At the request of the vessel, the SLSA were able to give the STEELFLOWER specific permission to continue her passage. The STEELFLOWER did not respond to the helm for a heading adjustment on passing Mile No. 11 and contacted the bottom at the side of the ship channel. With the vessel deeply laden and toward the east side of the ship channel, the failure to respond to the helm was likely due to bottom/bank suction. The pilot did not notify the SLSA because contacting the bottom reportedly did not involve an impact which would have suggested damage. The SLSA subsequently diverted the STEELFLOWER to Prescott to investigate the pronounced list the vessel developed as she continued through the Seaway. The damage discovered by divers on the port side of the vessel on 03 May occurred when she contacted the bottom at Mile No. 11. The STEELFLOWER was drawing in excess of Seaway draught and most likely contacted the bottom because the vessel experienced bank/bottom suction.Causes and Contributing Factors The STEELFLOWER was drawing in excess of Seaway draught and most likely contacted the bottom because the vessel experienced bank/bottom suction.